Biology 8 Flashcards
Cell cycle
The sequence of growth and division of a cell.
Chromosomes
Structures that contain DNA
Interphase
Majority of cells life spent in the growth period. Cell grows in size and carries on metabolism. Chromosomes are duplicated.
Mitosis
A cell enters a period of nuclear division. Two daughter cells are formed, each with a complete set of chromosomes. Cytoplasm divides, separating the daughter cells.
Prophase
The first and longest stage of mitosis. The long, stringy chromatin coils up into the visible chromosomes.
Sister Chromatids
Two halves of the same doubled structure. The DNA they contain is identical.
Centromere
Sister chromatids are held together by this structure. Plays a role in chromosome movement.
Centrioles
Small, dark, cylindrical structures that are made of microtubules. They are located just outside of the nucleus. Play a role in chromatin separation.
Spindle
Football-shaped, cage-like structure consisting of thin fibers made of microtubules. Play a vital role in separation of sister chromatids.
Metaphase
The short second phase. The doubled chromosomes become attached to the spindle fibers by their centromeres.
Anaphase
The third stage of mitosis. The centromeres split apart and chromatid pairs from each chromosome separate from each other.
Telophase
The fourth stage and final stage. Chromatids reach the opposite poles of the cell. Many things that happened in Prophase are reversed. Chromosomes unwind, the nucleolus reappears, the spindle breaks down, and a new nuclear envelope forms around each set of chromosomes.
Cytokinesis
The dividing of the cell’s cytoplasm after Telophase. Two new cells are separated.
Tissue
Cell growth and reproduction results in groups of cells working together.
Organ
Tissues organize in various combinations. Cells make us muscle tissue, and organ structures.
